This invention relates to a process for a treating stereotypic behavior in animals. This process is particularly useful in treating a specific stereotypic behavior, cribbing, in horses.
The term stereotypic behavior is used herein to describe the repetitive and pointless behavior frequently shown by domesticated animals and animals in captivity. This behavior has been observed, for example, in zoos where a caged bear or lion is seen pacing up and down the cage repetitively for many hours. Horses display a number of different stereotypic behaviors. These include cribbing, wind-sucking, weaving, head bobbing, head shaking, head nodding, pawing, stall walking, etc. Of these behaviors, cribbing and wind-sucking have long been recognized as a serious problem in this species.
Cribbing is often associated with aerophagia. A horse that exhibits this behavior typically grabs an object with its incisor teeth, then arches its neck, and by depressing the tongue and elevating the larynx, pulls backward and upwards and swallows air. As a result of this behavior, which is an acquired habit, the horse suffers many problems, including erosion of the incisor teeth, digestive disturbances, colic, flatulence, and weight loss. Consequently, owners of such horses will go to great lengths to prevent this behavior.
The typical treatment for this behavior includes mechanical prevention by use of throat straps and fluted bits as described for example in U.S. Pat. Nos. 3,687,112 and 3,308,791. Electric shock has been tried as another method of restraint. More radical treatment involves surgical excision of the throat muscles-Forssell's operation (Equine Medicine and Surgery, pages 758-759), or the creation of permanent buccal fistulas.
None of the above methods is entirely satisfactory. The mechanical methods do not prevent cribbing or wind sucking, but merely reduce the frequency by physical restraint. Furthermore, it is not always possible or desirable to maintain use of the mechanical restraint. The surgical measures result in disfigurement, and in any case, a successful outcome is not always guaranteed (The success rate is only about 25%).
It would be desirable to have a simple means of preventing stereotypic behavior that does not result in either mechanical constraint or surgical changes. The treatment is simple to administer and will have long-lasting effects.